Posted by Duane Spyer on Wednesday, 13 August 2014, at 9:39 a.m., in response to Re: Groove diameter, posted by Tom Trevor on Tuesday, 12 August 2014, at 10:48 p.m.

Well, I sent the slug to Matt Dardas from Dardas cast bullets. They offer a free service to measure 3 and 5 groove slugs. I assume that he used an anvil mic. to measure it. I certainly was surprised at the result. Regardless, I'm going to experiment with a no crimp load. I use Wolf's Lee 5 die set up which has a compression die and separate seating and crimp dies.